This has happened with 100% charge when I'm using apps (Although I haven't really checked to see which ones are causing it (Most likely Internet based ones though)

What will normally happen is that the phone will suddenly cut to a blank white screen and the only way I can get it to do anything is to battery pull and get it to reboot but at various stages of the reboot it crashes back to the white screen.

and like I said at the top of this post the only way to get my phone back working is to reboot while I have the charger plugged.

I've got a Curve 8520 on Australia's Optus network (Although I own it outright) I've had it for close to 3 years I think now.

It could be something else with the device, but I would try another battery, especially if you can borrow one. My thought is a failing battery can sometimes take a charge but not deliver under load. And you say it works when plugged in.

The genuine BlackBerry batterys are different according to the model BlackBerry, and that's all, though some BlackBerry models use the same model battery.

My advice is to use a genuine BlackBerry battery. Shope around. You don't have to pay full retail, but I would buy from a well known source and not buy the cheapest you can find.Posted via BlackBerryForums.com Mobile